Jean L. McCrory, PhD, the candidate for this Special Emphasis Research Career Award (SERCA), is an Assistant Professor at the University of Pittsburgh. Through mentorship and coursework, this SERCA award will help her achieve her career goals of becoming an independent, funded researcher, developing research collaborations with a number of well-respected scientists, and increasing her knowledge and competency in ergonomics, occupational medicine, biostatistics, and clinical research. She plans to apply for a NIOSH or NIH R01 award with the data acquired from this study. Her long term career goals are to develop a line of research studies on biomechanical issues unique to women in the workplace. Over 70% of pregnant women are employed. Pregnant women fall at a rate similar to that of women over the age of 70. The factors that contribute to this increased risk of falling are unknown, as little research has been performed to study gait and postural stability biomechanics during pregnancy. The purpose of the proposed research study is to investigate the changes to dynamic stability during level walking, stair ascent and descent, and perturbed stance in pregnant women. We hypothesize that, with advancing pregnancy, the following parameters will increase: the anterior position of the center of mass with respect to the base of support, the trial to trial intra-subject variability of selected gait parameters, the required joint torques, and the reaction time and response amplitude in response to a mild postural perturbation. Fifty pregnant women will be recruited to participate in this study. Data will be collected during each of the trimesters (2, 5, and 8 months). Fifty non-pregnant age and weight matched healthy women will serve as a control group, Women in the control group will participate in a single data collection session. An 8-camera video system interfaced with a force plate will be utilized to collect three-dimensional Kinematic and kinetic data of 10 trials of each subject during level walking, stair ascent and stair descent. A dynamic posturography system will be used to measure the subject's neuromuscular control in response to a mild perturbation during static standing balance. For the pregnancy group, a one-way repeated measures MANOVA will be performed for each dependent variable. A Tukey post-hoc analysis will be performed the significant values are present between visits. Additionally, to compare biomechanical stability of the pregnant women to the control subjects, a paired t-test will be performed on each dependent variable. Statistical significance will be considered at the probability level of p < 0.05.